Sunday, August 16, 2015

The Barn Swallows had me fooled!

This past spring, on April 22nd
to be exact, our Barn Swallows returned from their distant wintering quarters in Central and South America.I saw only five of them that day, and their
photo appears below.I was concerned that there were only five, significantly fewer than during
previous years.

I eagerly anticipated the nesting season that was about to commence. If there were only five Barn Swallows showing up this year, we certainly needed their population number to increase.As the days went by, however, I
was disappointed that I could not find any Barn Swallow nests on this
property.Memories of Barn Swallows
nesting on my porch in 2011 and 2012 as described in my book seemed
distant and vague.Besides, who was
going to catch all the flying insects this summer?Many flying insects are regarded as pests by humans,
and Barn Swallows have been valued for centuries as natural forms of pest
control.

Barn Swallows are adorable birds.They are amazingly intelligent, agile, and
comfortable in the presence of humans, at least in the presence of humans who
do not threaten them.What I like most
about Barn Swallows, however, is their relatively egalitarian social structure
as compared with many other songbirds. In the Barn Swallow species, both the male and female build their nest and feed their young. The male even helps incubate the eggs.

As the days passed, I began seeing Barn Swallows swooping under
the eave of the lower corner of the building where I live.In fact, the swallows would periodically
swoop at me during the mornings when I was in the yard refilling the bird feeders on the nearby tree.

Why were the swallows swooping at me, and what were they trying to
protect?I walked around the building
and inspected all of its eaves, searching for Barn Swallow nests.The photo on the right shows what a typical Barn Swallow nest looks like. After thoroughly inspecting all four walls of the building, however, I did not find any nests. I then decided to
investigate the corner of the building where I had seen the swallows swooping.

I ventured under the
eave and carefully inspected the wall and the ceiling of the overhang, but saw
no trace of a Barn Swallow nest, or at least the type of cup-shaped nest that
Barn Swallows build.What I did see,
however, intrigued me to no end.

A drainage pipe protrudes from the lower back wall of the
building.I discovered that the top of
the pipe, which is at a height of about eight feet (almost 2.5 meters) from the ground, was covered
with mud and straw.The inside pipe perimeter
also seemed to be lined with mud and straw, leaving an opening in the center of
the pipe.To the above left is a photo of the
pipe that I took on May 10th.

Can Barn Swallows nest inside a pipe?No, that seemed impossible.The pipe would have to lead to an open space inside
the building where they could build a nest.

Each day I kept wondering if a nest was being built on top
of the pipe.From my second-story porch,
I was unable to see the pipe itself, which protrudes from lower level of my
building and is obscured by the roof that overhangs it.

The photo to the right shows the view from my porch as I am looking toward the location of the pipe. The red arrow points to the location where the pipe is hidden underneath the eave. Therefore, in order to check the pipe each
day, I had to venture down the stairs of my porch and then turn back toward the
building. Once I approached the overhang, I could see the pipe.

A few weeks later, I
decided to be a bit more proactive.Just
in case the swallows were in the process of building a nest above the pipe, I
fabricated a ledge on which they could build it.I took a small rectangle of corrugated
cardboard and covered it with duct tape.I then attached the rectangle to the side and above the pipe, again with
duct tape. A little sloppy, but it was the best that I could do! You can see in the photo at the above left, taken July 17th, that the swallows eventually applied a little mud to the ledge.

Early one morning, I approached the pipe to find out if a
nest was being built on top of it.To my
surprise, three birds suddenly came flying out from under the eave and away
from the building!They flew out so
quickly that I surmised that they must have been perching on the cardboard
ledge I had affixed beside the top of the pipe.

After the three birds flew out and away from the eave, I ventured
closer to the pipe.Upon my inspection
of it, I found nothing different … just a pipe covered with mud, the inside of
the pipe lined with mud and straw, and a little mud on top of the ledge.

Intermittently over the next few weeks, as I watched from my porch, swallows were flying
to and from that corner of the building.One morning there were two swallows coming and going, each spending
only a few seconds under the eave and then departing again.

This made me wonder if the swallows were arriving at the pipe
with mud to build a nest on the duct-tape-covered ledge that I had set up.But no, my checking of the ledge did not
reveal any additional mud on top of it.

The swallow activity calmed down for a while, but a few
weeks later, I noticed it again.I began
to do some Internet research on whether Barn Swallows ever nest inside a
pipe.The only reference I could find to
such an activity was on a website forum where RV and camper owners were
complaining that Barn Swallows were starting nests inside the exhaust pipes of
their parked vehicles.The comments
indicated that the vehicle owners considered the swallows to be a nuisance.To rid the swallows and their nests from the
pipes, they would start their vehicle engines, causing the exhaust to blow the nesting
material away.Indeed, I found that the
diameter of the drainage pipe on my building was approximately the size of the diameter of the exhaust pipe on my car.

On the morning of June 22nd, there had been a whole flock of swallows swooping
toward the corner of the building and under the eave.The swallows seemed to be intent upon raiding
the area where the pipe was located.Through binoculars, I observed that some of the birds seemed to be Cliff
Swallows.

It made more sense to me that the pipe would be appropriate
for a Cliff Swallow nest rather than a Barn Swallow nest, especially if the
pipe led to a wider opening inside the building.This is because Cliff Swallows build nests
with small entrance holes and tunnels leading toward the inside of their nests.A pipe, if it indeed led to a wider space,
would seem to serve that purpose.

To the right is a photo of a Cliff Swallow nest. In fact, it is the nest on my porch that was originally built by Barn Swallows but modified by Cliff Swallows two years later. The entrance hole is part of a passageway that leads to the more open part of the nest.

Cliff Swallows, who usually nest in colonies, are known to raid their own nests.In the Cliff Swallow species, there seems to
be great competition for nests, supposedly because some Cliff Swallow nests are
built so poorly that they end up being destroyed by harsh weather conditions.Consequently, Cliff Swallows who have built a
faulty nest are often forced to usurp the nests of other Cliff Swallows.

Another reason that Cliff Swallows highly value other Cliff
Swallow nests is that they have a habit of removing an egg from their own nest
and placing it into another nest.Sometimes
they will first remove an egg from the other nest first.I have read that both the male and female
Cliff Swallows engage in this type of activity.

Yet on most mornings, the birds flying around the pipe were
Barn Swallows.And on only one
morning was there such a large number of birds flocking toward the corner of
the building.

As the summer progressed, I would sit on my porch each
morning.I continued to see a pair of
Barn Swallows, one-by-one, visiting the area of the pipe. Again, I could not see the pipe itself from my porch because it was obscured by the overhang (see previous photo).

In the late afternoons and evenings I would
again inspect the pipe, but it continued to
look the same as it previously had, with no nest visible. I never actually saw a bird fly in or out of the pipe. In order to do so, I would have to approach the pipe so closely that it would have given the birds ample warning not enter or leave the pipe.

There were several swallows on the roof of my building on
the morning of July 16th, as shown in the photo below, which I took
from my porch.This is the upper roof of
the building not shown in the photo, not the lower overhang under which the pipe is located.Since this upper roof is near the same part
of the building where the lower overhang and pipe are located, these birds
could have fledged from the nest inside the pipe, assuming, of course, that
there was indeed a nest inside the pipe!

The birds on the roof
were definitely Barn Swallows, not Cliff Swallows.One of them is shown in the photo to the
right.Although the breast color looks
light, the lack of a white patch on the forehead shows it to be a Barn Swallow. It is a juvenile, as shown by the continuous breast band. Unlike European Barn Swallows, our Barn Swallow adults have "broken", or discontinuous breast bands.

On July 17th, while I was sitting on the porch, a male
Barn Swallow flew toward the corner of the building, but landed on the nearby
fence when he saw me.I was able to take
a photo, which appears below.The discontinuous breast band, along with the rich colors on the rest of his plumage,
shows him to be an adult male.He didn’t
look too happy that I was in his presence!

On the morning of July 18th, there were numerous
swallow fledglings on the utility wire.After observing them closely through binoculars, I noticed that some of
them were Cliff Swallows!The photo below
shows a fledgling Cliff Swallow on the left.The three birds to the Cliff Swallow’s right are fledgling Barn
Swallows.

Where did all of these babies hatch?Had they fledged from a nest on my
building?Or perhaps their parents had
directed them to perch on that wire because the wire’s location gives a nice, wide
view of our valley, enabling the fledglings to more easily spot their parents
flying toward them to feed them.

Just eight days later, on July 26th, there were
even more swallows on the wire.Four of
them are shown in the photo below.

On August 1st,
I was out in my yard refilling the bird feeders on the tree.A Barn Swallow came flying from the corner of
the building and landed on the fence behind the tree.He allowed me to photograph him, and the
photo on the right proves him to have been an adult male.He could have well have been the same male as in the
previous photo taken on July 17th, with the sunlight hitting his
feathers differently.

On the morning of August
3rd, I counted 13 swallows on the wires.There was a group of seven on one wire and a
group of six on an adjacent wire.By
observing the birds through binoculars, I surmised that they were all
juveniles.The photo to the left shows two of them.These are both Barn Swallows.

I began to assume that Barn Swallows had indeed nested in
the pipe earlier in the summer.And
perhaps there had been not just one, but two nestings – two broods of swallow
babies who had fledged from that nest.

By August 12th, there were no more swallows on
the wires.But, on both the mornings of
August 13th and 14th, I observed a solitary swallow
circling high over the property.Although swallows are generally flocking birds, I wondered if this lone
swallow had been a male fledgling from the pipe nest who was viewing the nest’s
location one more time in order to claim the nest upon his arrival next spring.

Yes, a young male Barn Swallow will sometimes do this.He will return the following spring and claim
the nest in which he was hatched.He
will then proceed to attract a female to the nest, and if the female approves
of both him and the nest, the pair will mate, and the female will lay her eggs
in that nest.

I experienced this very phenomenon by observing my porch
nest during the summers of 2011 and 2012.It sounds unbelievable that a young Barn Swallow could fly to South America, only to return in the spring and find the
very nest in which he was hatched, but this has proven to be true!You can read a detailed narrative of it in
my book.

As of this date, all of our swallows have departed for their
long journeys south for the winter. The photo to the left shows the way the pipe looked on August 16th. Again, you can see that, although the swallows had applied mud and straw to the top of the ledge that I had installed for them, they had not build a nest there.

It
still remains a mystery as to how Barn Swallows could have nested inside the pipe.Even if I assume that
they did so, how did they do it?I do
not own the building and therefore do not know if the pipe leads to an open
space.If the pipe had not been a nesting place for swallows, why else would I have experienced
swallows swooping at me while I was walking around the yard near the corner of my building?And why did we have so many juvenile swallows
perching on the nearby utility wire?

Perhaps the mystery will be solved next spring.I plan to carefully observe whether any of
the returning swallows show interest in that corner of the building and the
pipe that protrudes from it.

In Bonding with the Barn Swallows, you can read about the unexpected location where one special male Barn Swallow perched all night and why he
perched there.You
can also read about how that
same Barn Swallow communicated to me on two occasions, once
through typical Barn Swallow twittering, and again by his body language
on the
utility wire while perched next to two other Barn Swallows. Two days later, an event revealed what he was trying to tell me.

Just click on the image to the upper right to find out more about the book. You can click on "Look inside" to see the Table of Contents and read the first few pages of the book. Or, you can click on "Surprise me" and read other pages!

4 comments:

So interesting!I know our barn swallows sometimes chose the most odd places to nest, here they did it beneath the tiles of my cottage one summer. That is usually where the house swallows nest otherwise.

No nesting swallows at my cottage this year though but still lots of them around. This year I'vce also seen a few Common swifts, not too common here normally though :-)

Those Cliff swallows sounds interesting :-) I wonder why they behave like that? placing eggs in other nests than their own?

Thanks so much for your comments, Christer! Do you mean that, with the cool weather you've been having, your swallows are still around? Lucky you!

We have Chimney Swifts here in the eastern US, although I have never seen any.

Cliff Swallows lead a rather barbaric existence. I wrote an article on how they modified the Barn Swallow nest on my porch in 2013 and took residence in it ... well, sort of. It's a rambling article, but if you scroll down, you can see pictures of the Cliff Swallows: http://www.deerkisshollowjewelry.com/barn-swallows.htm

Cliff Swallows are only found in the Americas, and they usually live in colonies of multiple nests. Here's a site about Cliff Swallows, stating (under "Cool Facts"): "Within a Cliff Swallow colony some swallows lay eggs in another swallow's nest. Sometimes the swallow may lay eggs in its own nest and then carry one of its eggs in its bill and put it in another female's nest." The site is at http://www.allaboutbirds.org/guide/Cliff_Swallow/lifehistory

I am not sure if Cliff Swallows place eggs in the nests of other species, but it's been documented that Cliff Swallows do that among their own nests. However, given the seemingly barbaric nature of Cliff Swallows, I wouldn't be surprised if they sometimes place their own eggs in Barn Swallow nests. There have been documented cases of hybridization between Barn and Cliff Swallows, meaning that a Cliff Swallow mates with a Barn Swallow, with the resulting babies having markings of both species. I have wondered if some of the swallow babies that were hatched in the pipe on my building were hybrids.